1. Field of the Invention
This invention relates to a quench hardening jig for a cylindrical work piece.
2. Description of the Prior Art
In conventional quench hardening of a machined cylindrical work piece, when a heated work piece is dipped into an oil bath, deformation occurs in the work piece due to shrinkage. To suppress this deformation to a minimum extent, a jig J1 shown in FIGS. 6, 7 is fit to, for example, an internal diameter of each end of a work piece W1 shown in FIG. 8 when it is dipped into an oil bath.
Because the above jig is formed so as to follow the internal diameter of a particular work piece W1, this jig cannot be used to a work piece having a different internal diameter. Thus, according to this conventional art, there is such an inconvenience that a different jig must be prepared depending on the internal diameter of each work piece.
Further, although the roundness of both ends of a work piece W1 can be realized with the conventional jig, there is a problem that the roundness of an intermediate section thereof is hard to secure. Additionally, because the conventional jig J1 is produced corresponding to the internal diameter of the work piece W1, when this work piece is dipped in an oil bath with the jig, that jig may be tightened by the work piece W1 if it may shrink. In this case, a procedure for removing the jig after dipping takes more time and labor than otherwise. Referring to FIGS. 6-8, reference numeral 10 denotes a ring like base member forming the jig J1 and numeral 11 denotes each of blocks disposed radiantly. A circle connecting an external periphery of each block agrees with an internal diameter of the work piece W1.